Bottom expander for paper cups



J1me 1960 D. a. LOESER ETAL 2,942,531

BOTTOM EXPANDER FOR PAPER cups 2 Sheets-Sheet 1 Filed July 20, 1959 INVENTORS DOA/Q40 5. 4.05652 June 28, 1960 D. B. LOESER ETAL BOTTOM EXPANDER FDR PAPER cups 2 Sheets-Sheet 2 Filed July 20, 1959 STE 5 INVENTORJ [Jon/n40 ,8. A 0555/? RE BODENDOEEFEE' BY United States Patent BOTTOM EXPANDER FOR PAPER CUPS Donald B. Loeser, Thiensville, and Raymond E. Bodendoerfer, Milwaukee, Wis., assignors to Paper Machinery Corporation, Milwaukee, Wis., a corporation of Wisconsin Filed July 20, 1959, Ser. No. 828,271

6 Claims. (Cl. 93-'36.5)

The present invention relates generally to machines for making paper cups of the fiat bottom or frustro-conical type. More specifically, the invention relates to a bottom expander for such a machine.

Machines of this general character at one of their operating stations employ bot-tom expanders which are moved axially in respect to a mandrel which holds the side wall and bottom portions of the cup together in assembled relationship. Heretofore, expanders and'finishing tools of this type have utilizedvarious devices for applying a radially outward rolling pressure to the bottom annular joint of the cup to properly form it and effect a tight seal between the previously glued bottom and side wall blanks. These prior art devices are often very complex and contain numerous parts which are not only subject to wear but costly to manufacture. In order to obtain the necessary pressures, various cam or eccentric arrangements have been proposed and/or wheels or segmented discs or rollers of various types. Many of these small parts are comparatively delicate and subject to malfunction and breakage and the devices in general were not always capable of ready and easy adjustment for varying their pressure.

In accordance with the present invention, an improved bottom expander has been provided which is rugged and simple in construction, contains relatively few parts, is easily adjustable and provides exceptionally good leverage for the bottom engaging tool. A considerable reduction in the number and complexity of parts has been effected by the present invention without sacrificing good adjustability or tool pressure.

These and other objects and advantages will appear later as this disclosure progresses, reference being had to the accompanying drawings, in which:

Figure 1 is a sectional view of a bottom expander mechanism in normal non-operating position, certain parts being broken away for clarity;

Figure 2 is a plan view of the mechanism shown in Figure 1, parts being shown as broken away and in section;

Figure 3 is a cross sectional view taken on line 3-3 in Figure 2, and

Figure 4 is an enlarged, fragmentary sectional view of part of the device shown in Figure l, the forming roller being shown in the bottom contacting position.

Referring more specifically to the drawings, the bottom expander mechanism M is slidably mounted on the gib plate 1 of the stationary frame F by means of its slide 2 which has a dove tail slide connection 3 with the gib plate. A suitably journalled drive shaft 4 has a cam track disc 5 fixed thereto having a cam track 6 formed in its upper side and in which the cam follower 7 is engaged. The follower is secured to the slide and rotation of the disc causes the follower, its slide and the expander mechanism in general to reciprocate relative to an axially stationary frusto-conical mandrel 10.

,At the bottom expander station shown in the drawings,

the mandrel 10.has the body blank 11 wrapped therearound and in the lower end of which has previously been inserted the bottom 12. The bottom and side wall of the cup together form an annular bottom flange 13 comprised of several layers of paper. When the mechanism M is advanced toward the mandrel sufiiciently, the forming roller 15 enters the flange. More specifically, an undercut rim 16 which forms a frustro-conical or dovetailannular surface that complements the inner surface of flange 13, is inserted into the flange.

At the same time that the rim 16 enters withinthe flange 13, a tapered aperture 18 of plate 19 is inserted over the end of the cup, with which it is complementary, and the roller applies radial pressure to the flange and against the tapered aperture as the roller is shifted radially by means to be described.

The forming roller 15 is rotatably mounted, by the anti-friction bearings 20, on a post 21 secured to a reciprocable slide 22. The slide has a pair of parallel guide flanges 23 which are slidable in their respective grooves 24 formed by the slide mounting plate-25 and the keeper bars 26. Cap screws 27 are threadably engaged in the front end of the sleeve member 28 andhold the bars 26 and plate 25 rigidly thereon. v

A retaining collar 30 is mounted around the roller and is held captive by snap ring 31 against the inside surface of plate 19 for sliding engagement therewith.

The plate 19, roller 15, collar 30 and snap ring 31 are quickly replaced by similar parts of different size for other size cups, simply by removing the cap screws 32 which hold the plate in place.

The slide 22 has a rectangular slot 34 formed in its rear central portion. A partially cylindrically shaped end 35 distance in the slot to accommodate arcuate movement of the arm end. The cylindrical-1y shaped end. 35 provides a long bearing contact with the slot and prevents twisting or binding of the slide in its gu-ideways.

The arm is pivoted on shaft 36a which is mounted within sleeve 28 and the rear ball end 37 of the arm extends a distance out from the rear end of the sleeve.

It will be noted that the lever arm 36 is of a considerable length and is resilient to a certain extent for a purpose more fully explained later.

The sleeve is rotatably mounted on suitable anti-friction bearings 38. and 39 within a tubular member 40." This tubular member in turn is slidable in a housing portion 43 of the slide 2, with-in the limits defined by the length of bolts 44. One end of each of these bolts is threadably engaged in the tubular member 40 while their other end slidably extends through a flange '45 on the housing portion 43. Springs 46 surround the bolts 44 and act to urge the tubular 11161111361110 the forward position in the housing.

A split clamping collar 48 is threaded onthe rear end of sleeve 28 and has a plurality of circum-ferentially spaced rods '49 secured therein by pins 50, and which rods extend rearwardly and are slidingly received in the rear section S2, to be described. The rods provide a connecting and driving means between the sections by which the sections are rota-ted together and are slidable relative to one another.

Thus, a forward section S1 is reciprocable on the reciprocable slide 2, and this section is comprised of the tubular member 40, the sleeve 28, arm 36, and the toolage located at the front end of these members. In turn, the sleeve 28, arm 36, slide 22 and the forming roller 15 are all rotatable as a unit within the tubular member 40.

The rearward section '82 is not reciprocable relative to the slide 2 but is rotatably mounted thereon by its drive shaft 51 in the anti-friction bearings 52 and S3.

The rods 49 extend through apertures 54 in the enlarged front end 55 of the drive shaft, and nuts 56 threaded on the rear ends of the rods limit the amount of extension between the sections, and also provide means through which the sleeve 40 is pulledto an inoperative position.

The shaft is rotatably driven, through its drive pulley 57, together with the sleeve 28 and its forming roller 15.

The enlarged end 55 of the drive shaft contains a surface which is inclined to the direction of reciprocation of the sleeve 28 and its arm 36. This surface takes the form of a tapered aperture 60 formed on the front end of the shaft. The ball end 37 of the arm extends into this conical socket and is urged against its inclined surface by the spring 62 acting against the other end of the arm.

An adjustment is provided for varying the relative position of the ball end 37 and its conical socket 60 so that the radial pressure exerted by the roller .15 can be varied. This adjustment takes the form of a pair of nuts 64 and 65 which are threaded on shaft 51, one on each side of the upstanding portion 66 of the slide 2. Thus, the axial position of the shaft 51 and its inclined surface 60 can be varied relative to the arm 36.

As shown in Figure 1, the slide is retracted to the left to the inoperative position in which position the ball end 37 is centrally offset from the axial centerline of the sections S1 and 52. In this position the slide 22 and its roller are axially aligned with the cup bottom.

Operation When the bottom forming operation is to be performed in timed relationship with other operating parts of the machine, the drive shaft 4 rotates to shift the main slide 2 forwardly to the right. At the time the roller rim 16 has fully entered the cup flange, continued forward movement of the front section S1 is arrested due to the projection 68 on the tubular member abutting against the adjustable stop 69 fixed on the frame F.

At this time the shaft 51 and consequently the roller 15 are rotating, and continued forward movement of the rear section S2 causes the now axially stationary ball end 37 to ride inwardly on the forwardly moving inclined surface 60. As a result, the roller 15 is shifted radially into engagement with the flange of the cup, tightly pressing it into contact with the aperture 18, thus expanding the flange and forming a tight bottom joint.

It is important to note that the arm 36 acts as a rigid leaf spring and has a certain amount of resiliency. This resiliency compensates for the varying thicknesses of paper which the roller encounters as it rolls around the periphery of the flange. Stated otherwise, at the lap joint What is claimed and desired to be secured by Letters Patent is:

1. In a bottom expander for paper cups having a front section and a rear section mounted for reciprocation together in a direction toward and away from a paper cup bottom to be expanded, an elongated and resilient arm pivotally mounted intermediate its length to said front section and extending generally in said direction, a forming tool connected with the forward end of said arm and mounted for movement transverse to said direction, said rear section having a surface inclined to said direction and engageable with the rear end of said arm, and means connecting said sections together to permit overtravel of the rear section relative to said front section, said inclined surface causing said arm to pivot and said tool to bear against said cup bottom when said overtravel occurs.

2. In a bottom expander for paper cups having a front section and a rear section mounted for reciprocation together in a direction toward and away from a paper cup bottom to be expanded, an elongated and resilient arm pivotally mounted intermediate its length to said front section and extending generally in said direction, said arm having a round rear end, a forming tool slide connected with the forward end of said arm and mounted for movement transverse to said direction, a rotatable roller mounted on said slide, said rear section having a socket with a tapered surface inclined to said direction of a cup of this type, there may be five layers of paper in one area of the flange and a lesser number in others. Because of the length and resiliency of the lever arm 36, the roller may shift very slightly in a radial direction as it travels around the flange, and evenly apply the necessary pressure all the way around for a properly formed bottom flange.

By means of the present invention, a simple and effective bottom expander has been provided which is economical to manufacture, rugged, and trouble-free in operation.

The overtravel of the rear section SI relative to the front section is readily adjustable to give the most desirable degree of finish.

The length of the arm provides good leverage without the use of numerous parts and the resiliency of the arm provides inherent pressure regulating of the roller against the flange being expanded.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the-subject matter 'which is regarded as the invention.

and engageable with said round end of said arm, and means connecting said sections together to permit overtravel of the rear section relative to said front section, said inclined surface causing said arm to pivot and said roller to bear against said cup bottom when said overtravel occurs.

3. In a bottom expander for paper cups having a slide including a rotatable rear section mounted for reciprocation in a direction toward and away from a paper cup bottom to be expanded, a front section carried by said slide for reciprocation therewith and also for movement relative thereto, an elongated and resilient arm pivotally mounted intermediate its length to said front section and extending generally in said direction, said arm having a front end of at least partially cylindrical shape, a forming tool slide mounted for movement transverse to said direction, said tool slide having a slot in which said arm front end is snugly received for oscillation therein, said rear section havingan actuating surface which is inclined to said direction and is engageable with the rear end of said arm, and means connecting said sections together to permit overtravel of the rear section relative to said front section and rotation together as a unit, said inclined surface causing said arm to pivot and said tool to bear against said cup bottom when said overtravel occurs.

4. In a bottom expander for paper cups having a slide mounted for reciprocation in a direction toward and away from a paper cup bottom to be expanded, a rear section rotatably mounted on said slide, a from section rotatably mounted on said slide, means for connecting said sections together for rotation as a unit and for movement relative to one another in the said direction of reciprocation to provide overtravel therebetween, an elongated and resilient arm pivotally mounted intermediate its length to said front section and extending generally in said direction, a forming tool slide connected with the forward end of said arm and mounted for movement transverse to said direction, and means forming a connection between said tool slide and arm front end for sliding and angular movement therebetween, said rear section having a surface inclined to said direction and engageable with the rear end of said arm, said inclined surface causing said arm to pivot and said tool to bear against said cup bottom when said overtravel occurs.

5. A device as defined in claim 4 including means for adjusting the relative position of the inclined surface and the rear end of said armto thereby vary the amount of ver'travei and consequently the pressure exertable by References Cited in the file of this patenf said resilient arm on said cup bottom. UNITED STAT PATENTS 6. A device as defined in claim 4 further characterized ES i in that said inclined surface is defined by a generally 2842'O33 Heyman July 1958 conical shaped hole and said arm rear end is generally 5 ball shaped. 

